The connector technology is well developed for coupling together electrical lines, fiber optic lines and other types of conductors that communicate different signals, including AC and DC power. There exists literally thousands of different types of connectors to fulfill the needs of numerous types of applications. Generally, connectors are constructed as two separable components, typically called a male connector and a female connector which, when joined, allow the signals and/or power to be communicated from one line to another line. As can be appreciated, long-term reliability of connectorized lines is of paramount importance.
A specialized area has developed for submersible connectors which allow the joining of lines for underwater applications. One type of underwater connector is adapted for mating and demating under dry conditions, but once mated, the joined connection can be immersed in liquids and yet maintain a reliable connection. In another type of underwater connector, the male and female connector components can be mated or demated while underwater and maintain reliable connections. The latter type of connectors are the most desirable for marine applications, in that the reliability of the connection is independent of whether the connector components are mated in wet or dry situations. Connectors that can be mated under water, known as "wetmate" connectors, generally include a pressure-compensated, dielectric liquid-filled chamber in the female half of the connector. During mating, the contact probe of the male connector passes through a penetrable entry seal of the liquid-filled chamber to connect with a female socket contact enclosed within the chamber. The penetrable entry seal maintains a seal to the male contact probe when mated, to thereby retain the compensating fluid within the chamber. The entry seal recloses when the male contact probe is removed. The penetrable entry seal tends to "wipe" the male contact probe so that the seawater, or the like, does not mix with the liquid dielectric contained within the pressure-compensated chamber. Underwater mateable connectors of such design are disclosed in U.S. Pat. Nos. 4,606,603; 4,666,242; 4,373,767; 5,194,012; 5,203,805 and 4,948,377, all by Cairns. Other types of underwater connectors are disclosed in U.S. Pat. Nos. 4,795,359 by Alcock et al.; 4,696,540 by Adams et al.; 3,845,450 by Cole et al.; 3,508,188 by Buck; and 3,491,326 by Pfister et al.
While the foregoing submersible connectors provide a reasonable degree of reliability, a need exists for yet a higher degree of reliability. For example, the connector described in U.S. Pat. No. 4,795,359 includes two or three nested, dielectric-filled bladders. The failure of the single shuttle piston is likely to allow the external liquid to enter each bladder and contaminate the dielectric, as well as the electrical contact bathed therein. In like manner, U.S. Pat. Nos. 5,203,805; 5,194,012 and 4,948,377 each describe a connector having a redundant entry seal to a dielectric-filled chamber. The entry to the connector has a plurality of interconnecting dielectric bath chambers with a wiping seal positioned between each such chamber. This type of connector essentially provides a single chamber with multiple wipers for the male electrical probe. Again, the failure of the single shuttle piston can lead to the contamination of the female electrical contact, despite the redundant entry seals.
Many of the submersible connectors that utilize a shuttle piston also employ a spring to return the piston to a rest position when demated. The spring not only increases the force necessary to mate the connector halves together, but can also cause an inadvertent demating of the connector halves.
From the foregoing, it can be seen that a need exists for a wetmate type of underwater connector that includes redundant bladders, whereby if one bladder, such as an outer bladder, becomes punctured or is otherwise rendered defective, the inner bladder can still function to maintain the female electrical contact free from contamination. Another need exists for a wetmate connector of the type where a penetrable seal associated with each of an inner and outer bladder is operable independently of each other, thereby improving the connector reliability.